VISCOELASTIC PROPERTIES OF PHARMACEUTICAL SEMISOLIDS .I. OINTMENT BASES

The rheological evaluation of semisolids by continuous shear methods is limited in its application. However if materials are viscoelastic, their properties can be assessed in creep testing where fundamental parameters are provided and rheological behavior can be represented by mechanical models. Measurements have been made on a number of ointment bases over a range of temperature. The addition of small quantities of complex materials to paraffin ointment bases changes their behavior from elastic to viscoelastic. As many of the materials show a characteristic change in viscoelastic spectrum with temperature it is hoped that creep testing will provide a suitable method for the correct rheological evaluation of many important materials. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company